Saturation of the inverse cascade in surface gravity wave turbulence

TL;DR

This paper reports the observation of an inverse cascade in surface gravity wave turbulence, showing a saturation effect influenced by wave steepness and nonlinear dissipative structures, expanding understanding of wave energy transfer.

Contribution

It provides experimental evidence of inverse cascade saturation in gravity wave turbulence and links it to nonlinear structures, a novel insight in wave turbulence research.

Findings

Inverse cascade observed at scales larger than forcing

Saturation depends on wave steepness

Nonlinear dissipative structures likely cause saturation

Abstract

We report on the observation of surface gravity wave turbulence at scales larger than the forcing ones in a large basin. In addition to the downscale transfer usually reported in gravity wave turbulence, an upscale transfer is observed, interpreted as the inverse cascade of weak turbulence theory. A steady state is achieved when the inverse cascade reaches a scale in between the forcing wavelength and the basin size, but far from the latter. This inverse cascade saturation, which depends on the wave steepness, is probably due to the emergence of nonlinear dissipative structures such as sharp-crested waves.